1. Field of the Invention
The present invention relates to a multi-section pulling rod structure, and in particular to a retractable and adjustable multi-section pulling rod structure.
2. The Prior Arts
In general, the retractable pulling rod is utilized on a luggage trunk, and usually, the retractable pulling rod used most frequently is made of a plurality of sockets, the number of sockets utilized depends on user's requirement. Since the length of each socket is fixed, so that in actual application, when the sockets of a pulling rod are fully extended or retracted, it is either too long or too short, thus causing inconvenience.
In order to overcome the shortcomings mentioned above, a minutely adjustable and positioning retractable pulling rod is proposed as shown in FIG. 1. Wherein, the retractable pulling rod structure includes: a parent tube 10, a child tube 12, and a positioning device 14. The positioning device 14 is disposed at one end of the child tube 12, and is composed of a sleeve base 16, an action element 18, a compression spring 20, and a positioning bead column 22. The top surface of the sleeve base 16 is connected to the action element 18, with its lower end provided with an action plate 182. The compression spring 20 is sleeved around a blocking portion 184 on the upper end of the action plate 182. The positioning bead column 22 is provided at the lower end of the action plate 182, so that a slide column 24 can be inserted from a side of the positioning bead column 22 to a slant slot hole 186 at the lower end of the action plate 182. The sleeve base 16 is provided with a slide guidance hole 162, which corresponds to a through hole 122 of the child tube 12, for the positioning bead column 22 to move therein. An action rod 26 is used to control the action of the positioning device 14. When the action rod 26 presses the action element 18 downward, the action plate 182 is brought to move downward, so that the compression spring 20 is compressed. Meanwhile, the slide column 24 is moved upward along a slant slot hole 186 on the action plate 182, so as to make the positioning bead column 22 to retract inward, to detach from a row of holes 102 of the patent tube 10. As such, the child tube 12 can be pulled and retracted freely in the parent tube 10. Similarly, in case that the action rod 26 is pulled to a predetermined length, and then it is released, thus the action element 18 is returned to its original position through the pressing upward of the compression spring 20. Meanwhile, the slide column 24 is moved downward along the slant slot hole 186 on the action plate 182, so as to make the positioning bead column 22 to extend outward, to insert into the row of holes 102 in the parent tube 10, in achieving extension or retraction of the pulling rod.
Though the pulling rod mentioned above can be positioned and adjusted according to the user's requirement, yet it still has the following drawbacks;
1. Since a row of holes are disposed on the parent tube, a multi-section retractable pulling rod can not be realized, so it has limitations in practical applications.
2. Since a plurality of holes (row of holes) are placed onto the parent tube (outer tube) for the child tube (inner tube) to be adjusted to extend or retract by means of the positioning bead column, therefore, its outer appearance is not aesthetically pleasing. Moreover, since dust and particles tend to get inside and gather in the tube through the holes, that could cause difficulty in extending and retracting the child tube along the parent tube. Also, its is rather difficult to remove the dust and particles from the tube in causing quite inconvenience.
Therefore, presently, the design and performance of the retractable pulling rod of the prior art is not quite satisfactory, and it has much room for improvements.